Pulse activated actuator pump system

ABSTRACT

A pump for moving a fluid includes an actuator housing having a chamber for housing the fluid. The chamber has ports for accommodating fluid flow through the chamber. A plurality of individual actuators are located in the chamber and in contact with the fluid. Completing the pump is an actuator for sequentially activating individual actuators, wherein each actuator, when activated, changes dimensions and exerts a displacing force on the housed fluid.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/448,771, filed Feb. 24, 2003.

FIELD OF INVENTION

[0002] This invention concerns pumps and, more specifically, is directedto a programmable actuator pump system for moving a fluid at adetermined rate and in a determined flow path.

BACKGROUND

[0003] Many kinds of pumps are known in the art and adaptations havebeen made for specific applications. Pumps for moving fluids are poweredby motors that drive moving components, usually pistons and valves, toproduce a force on a fluid that causes it to flow. Valves in such pumpsystems are generally activated by electromechanical devices such assolenoids and other mechanical components. As one of skill in the artwill appreciate, there are countless versions of pumps for manydifferent applications. In the medical device field, e.g., there areperistaltic pumps, diaphragm pumps and centrifuge pumps for deliveringblood and other biological fluids for specific purposes. Pumps used inmany of today's modern chemical processes, including oil or petroleumrefining, food and drug manufacturing and electric generation, relyextensively on a complex interconnection of pumps, piping and valves toeffect a particular chemical conversion or mixture. The reliance onmultiple dedicated pumps or redundant valve configurations results incomplex, expensive systems that require high maintenance andmanufacturing costs.

[0004] Polymer actuators, requiring no moving parts, are often used inthese complex systems to simplify valve operation. A class of actuators,electroactive polymers (EAP—known as artificial muscles), has recentlybeen developed. See, e.g., “Electroactive Polymer (EAP) Activators as anArtificial Muscles” Yoseph bar-Cohen Ed., Society of Photo-OpticalInstrumentation Engineers, Publisher (2001). Electroactived polymersreversibly swell or change form when activated. The mechanical forceexerted by activated EAP is captured to move components in actuatordevices.

[0005] U.S. Pat. No. 6,664,718 describes monolithic electroactivepolymers that act as transducers and convert electrical energy tomechanical energy. The EAP are used to generate mechanical forces tomove components of robots or pumps.

[0006] U.S. Pat. No. 6,682,500 describes a diaphragm pump powered byEAP. In this pump, an EAP is positioned beneath a flexible membranetermed a “diaphragm”. As the EAP is activated, it swells and contractsand thereby reversibly moves the diaphragm which in turn displacesliquid in which it is in contact. The diaphragm pump uses check-flowvalves to control liquid flow.

[0007] U.S. Pat. No. 6,685,442 discloses a valve actuator based on aconductive elastomeric polymer gel. In operation, the conductive gelpolymer is activated by an electrolyte solution. By manipulating thepotential across the gel, the motion of an elastomeric membrane over theexpanding gel and the electrolyte solution can be controlled to act as a“gate” to open or close a fluid channel as a check-valve for thatchannel.

[0008] The use of actuators in pump systems reduces the complexity ofsystem operation. Yet each of the disclosed pumps that incorporatepolymeric actuators still requires moving parts and valves. Themechanical complexity, maintenance expense, large size and weight,sterility problems, fluid-contaminating erosion products, chemicalincompatibility with certain fluids and often noisy operation, make mostpump systems unsuitable for certain purposes.

[0009] Accordingly, simple actuator devices that use no mechanical partsor valves have been sought.

SUMMARY

[0010] Improved pumps and methods of pumping fluids are hereinafterdisclosed which overcome many of the disadvantages of prior art pumps,including the use of complex moving parts and the relatively high costof manufacture.

[0011] The present invention contemplates an actuator pumping systemthat utilizes the force of expanding or deflecting actuators inside ahousing of fixed volume to displace liquid through the housing. Nomoving parts or valves are required. The timed activation of individualactuators causes the actuators to change dimensions at a determined timeand sequence and thereby cause the fluid to flow at a certain time andpath.

[0012] The present pump system for moving a fluid comprises an actuatorhousing having a chamber for housing the fluid, a plurality ofcontiguous actuators located in the chamber, and activating means forsequentially activating individual actuators. Each actuator, whenactivated, changes dimensions and exerts a displacing force on thehoused fluid.

[0013] In preferred embodiments of the present invention, the actuatorhousing comprises two or more chambers in fluid connection. In certaininstances, the separate chambers may be programmed to displace differentsegments of fluid at individualized rates and flow paths The separatechambers may, e.g., be used to modify flow rates of fluids that changeviscosity while moving through the housing. In other instances,coordination of flow rate through the separate chambers may be used tosubdue any pulsing flow patterns from individual chambers into a smoothcontinuous fluid flow pattern downstream from the chambers.

[0014] Preferably the pump comprises a means for controlling theactuator activating means whereby individual actuators are activated ata determined time. The controller in preferred embodiments is aprogrammable microprocessor in electrical connection with the activatingmeans.

[0015] In certain instances, the pump comprises a sensor means fordetermining physical properties of the fluid. The sensor is inelectrical connection with the controlling means and provides feed-backabout the physical state of the fluid to the controlling means. Thesensor may, for example, measure changes in pH, viscosity, ionicstrength, velocity, pressure or chemical composition of fluid. Thisfeed-back allows the pump to interactively alter fluid flow rate anddirection.

[0016] In preferred embodiments of the present invention, the pump movesa fluid at a controlled rate. In these embodiments, the activating meanssequentially activates individual contiguous actuators at a selectedtime. The rate at which the fluid flows depends on the rate of actuatoractivation and volume displaced by each actuator. Thus, in certainpreferred instances, the individual actuators are repeatedly pulsedsequentially at rapid intervals, and liquid is essentially spurted fromthe housing. In other instances, a first group of contiguous actuatorsis activated at a certain time and then, while the first group return totheir original dimensions, a second group of contiguous actuators issequentially activated. Repetition of this activation pattern forseveral times or with more groups of actuators along the fluid flow pathcauses a volume of fluid to be displaced and eventually to be ejectedfrom the housing. The amount of fluid displaced in a given time isdetermined by the difference in volume between activated actuatorsrestored activators.

[0017] The chamber in the actuator housing is sufficiently rigid toprevent it being deformed by the force exerted by activated actuators,since the displacing force of the activated actuators requires thechamber to maintain an essentially constant volume. In certaininstances, however, as when the pump is to be placed into a smallcavity, the actuator housing may be slightly deformable while beinginserted.

[0018] In other preferred embodiments of the present invention, thedirection of fluid flow inside the actuator housing is controlled. Inthese embodiments, the location of individual actuators in the chamberdetermines the flow path of the displaced liquid. A fluid directedthrough the chamber will flow into spaces that contain no actuator tobar fluid flow. In certain preferred instances, the individual actuatorsare located in a grid pattern within the chamber with individualactuators positioned at the intersection of each grid line. In theseinstances, a fluid flowing through the grid will move into unobstructedspaces as defined by the position of actuators in the grid, but will notflow into volumes barred by actuators. Other actuator patterns may bedesigned to cause different flow paths. Most preferably the pumps inthese embodiments comprise sensors for determining properties of thefluids. Pump controllers may be programmed to respond to feedback fromthe sensors and activate selected actuators and thus interactivelydetermine the fluid flow path.

[0019] In certain instances, the chamber may comprise more than oneinlet port for receiving different fluids with each fluid being directedinto separate paths. In these instances, the pump may be used as a fluidmixing device by making the flow paths of different fluids intersect.The mixed fluids may be allowed to react and are then directed to anexiting flow path.

[0020] In other preferred embodiments of the present invention, thepumps move fluids at both a determined rate and in a determined path. Inthese instances, the rate and pattern of sequential activation ofactuators in the pump determines the rate of fluid flow and thepositioning of actuators in the chamber of the actuator housingdetermines the flow path.

[0021] The actuators for use in the present invention are preferablyessentially inert and non-reactive with the fluid. In those instanceswherein the pump is used for moving a biological fluid, blood e.g., theactuators are biocompatible with the fluid. In other instances thechamber comprises an elastomeric impermeable lining located between theactuators and the housed fluid to prevent contact of actuators andfluid.

[0022] In preferred embodiments of the present invention, eachindividual actuator is encased in an essentially inert material toprotect it from contact with fluid and, in certain instances, frominteraction with contiguous actuators. The individual actuators whenencased are individual integral cells inside the actuator housing.

[0023] The actuators of the present pump are most preferably comprisedof elastomeric materials responsive to an activating means. Theelastomeric material changes its dimensions when activated. In certaininstances the material expands and, due to the barrier to expansionexerted by contiguous actuators, moves linearly outward into a spaceoccupied by the housed fluid and thereby displaces the fluid. In certainother instances, activation of the polymer causes it to contract into asmaller volume, making the space above it open for fluid flow. Incertain other instances the elastomeric material changes shape. As theshape change occurs, the elastomeric material pushes and displaces theliquid. It is an essential aspect of the present invention that theactuators quickly revert to their original shape when not activated. Itis the reversible nature of the actuators that supports the pumpingaction.

[0024] Most preferably the actuators in the pump of the presentinvention are reversibly responsive elastomeric materials selected fromthe group consisting of electroactive polymers, electrolyticallyactivated polymer gels, optically activated polymers, piezoelectricpolymers, piezoelectric ceramic materials, chemically activatedpolymers, magnetically activated polymers, thermally activated polymersand shape memory polymers. The shape and size of the actuators isdetermined by the dimensions of the chamber, the amount of size changewhen the actuators are activated and the nature of the fluid beingmoved.

[0025] In preferred embodiments of the present pump, the actuatorscomprise electroactive polymers. In certain instances, the activatingmeans is an electrical circuit that directly triggers individualactuators to change dimensions at a determined time and pattern.Chemical changes such as pH, ionic strength or phase changes in theelectroactive polymers resulting from direct electrical activation causethe actuators to change size or shape. Piezoelectric polymers andpolymers fitted with electrical contacts are examples of actuatorssuitable for use in these embodiments. In embodiments with electroactivepolymers, each actuator is electrically shielded from contiguousactuators.

[0026] In other preferred embodiments of the pump of the presentinvention, the actuators are electrolytically activated polymer gelsthat are activated by contact with an electrolytic solution. In theseembodiments, individual polymers are each encased with a semi-permeablematerial, the actuator housing comprises a reservoir for housingelectrolytic solution and the activation means is an electrical circuitwhereby electrolytic solution is caused to flow reversibly through thesemi-permeable material from the reservoir into contact with and awayfrom the polymer to cause reversible movement of the actuator.

[0027] In those preferred embodiments wherein actuators are activated byan electric circuit either directly or by electrolyte, the pumppreferably comprises a remote control device for driving the circuit.Most preferably the remote control device is infra-red orradio-frequency driven. In certain preferred embodiments the remotecontrol device is driven by a microprocessor programmed to operate thepump at a selected time and sequence.

[0028] In other preferred embodiments of the pump of the presentinvention, the actuators comprise optically responsive polymers. Incertain preferred instances, the optically responsive polymers areionized in the presence of light. In other preferred instances, theoptically responsive polymers change pH in the presence of light. Theactivation of the optically responsive polymers is controlled byexposure to a laser beam of specific wavelength, to natural light, to aLED or to other quantum light sources. In certain preferred instances,the time of exposure is controlled by a remote control device, aninfra-red or radio-frequency driven device, e.g. In these preferredembodiments the remote control device is driven by a microprocessorprogrammed to activate the actuators at a selected time and sequence.

[0029] In one embodiment of the present invention, the pump may be usedas a fluid mixing device. These embodiments are especially useful inchemical processing or bio-processing systems. For chemical processing,the device may accommodate more than one fluid and each fluid may becaused to flow in a chosen flow path into a reservoir and then out fromthe reservoir as a single fluid. In bio-processing systems the devicemay be used as a gentle cell processing device.

[0030] In other embodiments, the pump may be used as a portable fluiddelivery device. Because the pump is simple and comprised of lightweightcomponents, it is useful in stealth operations.

[0031] In another embodiment, the pump may be used as an infusion pumpfor delivering a medicament to an individual in need thereof. Theinfusion pump may be manufactured at low cost and therefore bedisposable after a single use. In other instances, the infusion pump maybe very small and of a size permitting implantation in the individual ifnecessary. Such devices may comprise a fluid sensing device and areespecially useful for controlled delivery of insulin to diabetics.

[0032] In yet another embodiment, the pump may be used as a drugdelivery device for delivering a liquid drug or drug solution at acontrolled rate and at a controlled time to an individual in needthereof. The delivery device may be used to deliver medicaments tohumans, dogs, cats and other animals. In certain embodiments of the drugdelivery device, the actuator housing comprises a single outlet port butno inlet port and houses the liquid drug or drug solution to bedelivered. These devices may be preloaded with drug or drug solution andmay be kept sterile until use.

[0033] In other preferred embodiments of the present invention, the pumpmay be used to propel an object along a surface. In these embodiments,the pump comprises an actuator housing in contact with the object, aplurality of contiguous actuators in contact with the actuator housingand in contact with the surface, and activating means for sequentiallyactivating individual actuators. In this embodiment, when each actuatoris activated, it changes shape and exerts a displacing force on thesurface and thereby propels the solid object in a direction oppositethat of the displacing force. The propelling pump may be used to propelan object suspended on a liquid surface, on a solid surface or forpropelling an object submerged in a liquid.

[0034] The present invention also sets forth methods for pumping a fluidat a controlled rate. In the methods, the actuator housing of thepresent pump is placed into fluid contact with fluid to be pumped, afirst actuator is activated to prevent back-flow from the actuatorhousing and then the contiguous actuators are repeatedly activated at asequence wherein activation of one of the individual actuators occurs ata time after one of its contiguous actuators has been activated.

[0035] The methods may be used to pump fluids of different viscosities.In these methods, the pump comprises two or more chambers in fluidconnection and each chamber is operated at a different flow rate byactivating the actuators therein at different times and sequences.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other aspects, features and advantages of thepresent invention will be more apparent from the following moreparticular description thereof, presented in conjunction with thefollowing drawings wherein:

[0037]FIG. 1 illustrates the pump of the present invention depicting theactuator housing with a chamber for housing the fluid, a plurality ofcontiguous actuators in the chamber, and activating means forsequentially activating individual actuators. A controller foractivation means and a fluid sensor are illustrated. Flow of fluidthrough the housing is depicted. In operation, the individual actuatorsare activated at a time and in a sequence that causes fluid flow at adetermined rate and path.

[0038]FIGS. 2a-2 c illustrate possible arrangements of contiguousactuators in the chamber. In FIG. 2a the contiguous actuators arelocated in a linear array in the chamber. In this embodiment, theactuators, when activated, expand to the opposite wall of the cavity andform a seal that bars fluid flow and at the same time displace fluidalong the axis of the array. FIG. 2b illustrates actuators locatedapposite in two linear arrays. In this embodiment, the actuators, whenactivated expand into contact one with another. FIG. 2c illustratesactuators located in a spiral array along the axis of flow inside thecavity. This array is useful for vertical movement of fluid.

[0039]FIG. 3 illustrates the pump with a plurality of sets of contiguousactuators in the chamber. Fluid flow caused by sequential activation ofthe contiguous actuators is indicated.

[0040]FIG. 4 illustrates the pump of the present invention with threechambers in fluid connection inside the actuator housing.

[0041]FIG. 5 illustrates the pump for moving a fluid in a determinedpath wherein the actuators are located in the chamber at positions thatdefine the flow path for the liquid when displaced. In this illustrationthe contiguous actuators are located at the intersection of grid linesdefining a matrix.

[0042]FIG. 6 is an expanded view of the actuators in chamber. Theactuators comprise photo-activated polymers and are encased in an inertmaterial. Conduits for access to a photo-source are illustrated. In thisembodiment, the fluids may be pumped at a controlled rate and direction.The fluids may be directed to an intersection where they mix and areallowed to react.

[0043]FIG. 7 depicts pump 10 in an on-line processing system whereinvarious fluids are directed into a main flowing fluid path at adetermined time. This pump may be produced as a modular unit forinsertion into a chemical or bio-processing system.

[0044]FIG. 8 illustrates possible placements of contiguous actuators 12in chamber 14. FIG. 8A depicts the actuators on a chamber wall situatedso that each actuator expands to an opposite hard surface, an oppositewall of the chamber or another surface in the chamber. FIG. 8B depictsthe actuators situated apposite in the chamber. In this configuration,the actuators will expand into contact with the other.

[0045]FIG. 9 illustrates pump 10 having electroactive actuators 12 thatare activated by contact with electrolytic solution. Actuator housing 11comprises chamber 14 and reservoir 27 for housing electrolyte solution28. Electrode 29 is located in the actuator and electrode 30 is locatedoutside the actuator. Frit 31, a semi-permeable grid, separates actuatorand electrolyte solution. A semi-permeable membrane 32 surrounds theactuator.

[0046]FIG. 10 illustrates the pump as a propulsion device. FIG. 10aillustrates the pump for moving an object along a surface. FIG. 10billustrates the pump for moving an object suspended in a liquid.

[0047] Other features and advantages of the present invention will beapparent from the following detailed description, the accompanyingdrawings and the appended claims.

DETAILS OF THE INVENTION

[0048] Definitions

[0049] “Activating means” refers generally to the means by which thepolymeric actuators are caused to change dimensions. In the case ofelectroactive polymeric gels that are activated directly, the activatingmeans is a switching means that triggers the electrical circuit thatcauses electric activity resulting in the chemical action in the polymerthat causes dimension change in the polymer. In the case ofelectroactive polymeric gels that are activated indirectly, theactivation means causes flow of electrolytic solution into contact withthe polymer and then away from polymer. In the case of light-activatedpolymers, the activating means is the switching means that allows lightto contact the polymer. In the case of piezoelectric actuators, theswitching means is generally the switching means that electrical orphysical pressures to the piezoelectric material.

[0050] “Controlling means” refers to controllers in electrical contactwith the activating means. Preferably the controlling means is anelectronic device that is programmed to provide activation of activatingmeans at a chosen time and sequence. Most preferably the controllingmeans comprises a programmed microprocessor. Microprocessor chipswell-Submitted known in the art. A simple chip is inexpensive and ispreferably used in embodiments of the present invention that aredisposable.

[0051] “Fluid” refers to liquids, slurries, fine powders, emulsions andmixtures of solvents. In certain instances the fluid may be a gas.

[0052] “Microprocessor” means computer as well as the CPU in thecomputer. Preferably the microprocessor is a small chip that may beprogrammed to run the pump at a selected time and sequence. Themicroprocessor may interactively respond to the sensor. Certain chipsthat very inexpensive to manufacture are quite suitable for disposableembodiments of the present pump.

[0053] “Sequential activation” means a pattern of activation ofcontiguous actuators wherein neighboring actuators are activated oneafter the other. In an array of contiguous actuators, activation of thefirst actuator determines a volume of fluid to be displaced. Activationof the neighboring actuators will displace this volume. Repetition ofactivation sequentially will continue to move this volume along thesurface of contiguous actuators through the chamber. The sequentialactivation of contiguous actuators resembles the sounding of keys on apiano board when a musical scale is played. The present pump however isnot limited to a flat linear array of actuators. A tubular chamber may,e.g. comprise actuators in a spiral array. In certain embodiments, acombination of multiple actuators may be activated at the same time todisplace a greater volume of fluid and increase flow rate. In theseembodiments, “sequential” means activation of contiguous sets ofactuators.

[0054] Actuators for use in the present invention preferably compriseelectroactive polymers (EAP). These polymers respond to externalelectrical stimulation by displaying a significant shape or size change.EAPs fall into two major categories: electronic and ionic Electric fieldor Coulomb forces generally drive electronic EAPs, while the primarydriver for ionic EAPs is the mobility or diffusion of ions.

[0055] Types of electronic EAP include ferroelectric polymers,dielectric polymers, electrorestrictive graft polymers, electrostrictivepaper, electrovasoelastic polymers and liquid crystal elastomer (LCE)materials. Ionic EAPs include Polymer Gels (IPG), IonomericPolymer-Metal Composites (IPMC) Conductive Polymers (CP)and CarbonNanotubes (CNT). The following Table I on ionic EAPs may be found on theAZom website athttp://www.azom.com/details.asp?ArticleID=885#_Ferroelectric_Polymers:TABLE I Polymer Gel (IPG) These are polymer gels having the potential ofmatching the force and energy density of biological muscles. Thepolyacrylonitrile materials are activated by chemical reaction(s), achange from an acid to an alkaline environment inducing an actuationthrough the gel becoming dense or swollen. The actuation is somewhatslow due to the diffusion of ions through the multilayered gel.Ionomeric Polymer-Metal Composites (IPMC) These are EAPs that bend inresponse to an electrical activation as a result of the mobility ofcations in the polymer network. Generally, two types of base polymersare employed to form IPMCs these are Nafion ® (perfluorosulphonatemanufactured by Du Pont) and Flemion ® (per- fluorocaboxylatemanufactured by Asahi Glass, Japan). IPMC require rela- tively lowvoltages to stimulate a bending response (1-10 V) with low frequenciesbelow 1 Hz. Conductive Polymers (CP) CPs actuate via the reversiblecounter-ion insertion and expulsion that occurs during redox cycling.Significant volume changes occur through oxidation and reductionreactions at corresponding electrodes through exchanges of ions with anelectrolyte. Electrodes are commonly fabricated from polypyrrole orpolyaniline, or PAN doped with HCI. CP actuators requires voltages inthe range of 1-5 V. Variations to the voltage can control actuationspeeds. Relatively high mechanical energy densities of over 20 J/cm3 areattained with these materials, however, they posses low efficiencies atlevels of 1%. Other material combinations for CP are polypyrrole,polyethylenedioxythiophene, poly(p-phenylene vinylene)s, polyaniline andpolythiophenes. Some applications reported for these CPs are miniatureboxes that have the ability to open and close, micro-robots, surgicaltools, surgical robots that assemble other micro-devices. CarbonNanotubes (CNT) In 1999, CNTs emerged as formal EAPs with diamond-likemechanical properties. The actuation mechanism is through an electrolytemedium and the change in bond length via the injection of charges thataffect the ionic charge balance between the nano-tube and theelectrolyte. The more charges that are injected into the CNT the largerthe dimension change. As a consequence of the mechanical strength andmodulus of single CNTs and the achievable actuator displacements, theseEAPs can boast the highest work per cycle and generate much highermechanical stresses than other forms of EAPs.

[0056] As can be observed in Table I, the mechanical properties andchemical mechanism of the ionic EAPs vary considerably. For use in thepresent invention, EAPs that exhibit significant and reversible volumechanges when activated are preferred. Examples of preferred polymerswith a significant bending response include the base polymers Nafion®(perfluorosulphonate manufactured by Du Pont) and Flemion®(perfluorocaboxylate manufactured by Asahi Glass, Japan).

[0057] A second category of actuators that may be used in preferredembodiments of the invention comprise photo-activated polymers termedphoto-actuators. Photo-actuators cause changes in the length and volumeof an illuminated material. Examples of mechanisms behindphotoactivsation include phase transitions, internal restructuring(isomerization) in polymers, and photostriction (a combination of thephotovoltaic and piezoelectric effect).

[0058] U.S. Pat. No. 6,143,138 discloses light activated polymers usefulas actuators in the present invention. The polymer comprises a pH jumpmolecule, preferably anthracene. Visible light is used to excite the pHjump molecule. The attendant pH change occurs rapidly (in nanoseconds)and can be maintained by continuous wave light or by an appropriatelypulsed light.

[0059] Suitable polymers for use as the present actuators are wellknown, and new materials are continuously being discovered that will besuitable actuators. A review of electroactive polymers may be found in“Electroactive Polymer (EAP) Activators as an Artificial Muscles” Yosephbar-Cohen Ed., Society of Photo-Optical Instrumentation Engineers,Publisher (2001) herein incorporated in its entirety.

[0060] Although certain reversibly expanding polymers suitable for useas actuators in the present invention have herein been disclosed, anymaterials having specifications including reversible, quick shape andvolume changes when activated, low voltage requirements, good strain androbustness will be suitable. It is intended that the scope of thepresent invention extends to new materials that will be developed thatexhibit the required specifications.

[0061]FIGS. 1-10 show generally the preferred embodiments of the pump ofthe present invention designated by the numeral 10.

[0062] Referring now to FIG. 1, Pump 10 includes actuator housing 11,chamber 14, a plurality of contiguous actuators 12 located in chamber14, and activating means 13 for sequentially activating individualactuators 12. The actuator housing may have one or more inlet ports 15and one or more outlet ports 16.

[0063] Also illustrated in FIG. 1, is controller 21. Controller 21controls activating means 13 and establishes the times at whichindividual actuators are activated sequentially. Such controllers arewell known in the art. Preferably the controller 21 is a programmablemicroprocessor, most preferably a simple programmable microchip inelectrical connection with the activating means.

[0064] Also illustrated in FIG. 1 is a sensor 22 for determining certainphysical properties of the fluid wherein the sensor is in electricalconnection with the controlling means and is capable of deliveringsignals received from the fluid to the controlling means. Sensors forthe purpose are well known in the art and may respond to physicalproperties of the fluid including chemical composition, pH, pressure,temperature and flow rate.

[0065]FIGS. 2a-2 c illustrate possible arrangements of contiguousactuators in the chamber 14. In FIG. 2a the contiguous actuators 12 a-eare located in a linear array in the chamber 14. In this embodiment, theactuators, when activated, expand to the opposite wall of the chamberand form a seal that bars fluid flow and at the same time displace fluidalong the axis of the array. FIG. 2b illustrates actuators 12 a-elocated apposite in two linear arrays. In this embodiment, theactuators, when activated, expand into contact one with another. FIG. 2cillustrates actuators 12 a-e located in a spiral array along the axis offlow inside the cavity. In this embodiment, the actuators, whenactivated expand into contact with the opposite wall. This array isuseful for vertical movement of fluid along the axis of the flow in theactuator housing. These examples are illustrative of actuatorpositioning, but other positions that provide for contact of expandedactuators with a solid surface to displace fluid are possible.

[0066] Displacement of fluid is achieved by activating each contiguousactuator individually in a sequential time pattern. The elastomericmaterials in the actuators, upon activation, change dimensions and exerta force on the volume of liquid in which they are in contact. The forceexerted by each actuator in a contained fluid is multi-directional, andalthough the fluid is displaced, there is no flow created. Fluidmovement is achieved in the present invention by activating contiguousactuators sequentially to cause individual actuators to expand to anopposite surface and displace the volume of liquid corresponding to theexpanded size of actuator. A first actuator in the array is activated,expands to an opposite surface and exerts force on the fluid. Fluiddisplaced by this first actuator will move in forward and backwarddirections relative to the actuator. But when the second actuator, whichis contiguous to the first actuator, is activated, it displaces fluid inone direction only because the other three directions are blocked by thefirst actuator, an opposing surface and a wall of the chamber to whichthe actuator is attached. By continuing the sequential activation ofcontiguous actuators the fluid is forced to flow along the path definedby the actuators and the housing. In preferred embodiments, sets ofactuators are position in the chamber along the axis of flow. Repetitionof the activation sequence continues with each set until the first setof actuators reverses its shape change and is then be activated again.Reversal of flow may be achieved in the present pump by reversing thesequence of activation of the individual actuators. Certain polymerscontract when activated. When used as actuators in the presentinvention, the extended first actuator is placed at the entry port ofthe chamber. The activation pattern begins by contraction of the firstactuator followed by sequential contraction of contiguous actuators.Fluid flows along the path defined by the actuators.

[0067]FIG. 3 illustrates the pump 10 with a plurality of contiguous setsof contiguous actuators, set 17 a-e, set 18 a-e and set 19 a-e arrangedin sequence in chamber 14. Fluid flow in this illustration occurs inphases wherein, in a first phase, the first set of actuators 17 a-e issequentially activated and in a second phase the second set of actuators18 a-e is then sequentially activated. The volume of liquid displaced bythe first set 17 a-e will flow into position above the second set 18a-e. Repetition of these phases results in pulsed flow of liquid throughand out of the actuator housing.

[0068] The rate of flow through the actuator housing 11 is determined bythe selected time and sequence of activation of the actuators.Calculation of expected flow rate may be made from the change indimensions of the actuators. The amount of fluid displaced at a giventime is the sum of the total volume of all the expanded (or contracted)actuators during this time. The rate of fluid flow is the volumedisplaced during a given time which is determined by the time andsequence of activation. The controller 21 may be programmed to activatethe actuators at a given time and sequence to provide a selected flowrate.

[0069]FIG. 4 illustrates the pump 10 of the present invention comprisingthree chambers 14 a, 14 b and 14 c. In this illustration the chambersare located in fluid connection. Each chamber may be operatedindependently of the other so that fluid flow may be initiated atdifferent times and sequences. This arrangement is useful for pumpingfluids that may change viscosity during fluid flow. It is also usefulfor damping a pulsed flow. Dampening may be achieved by positioning theactuators in a parallel arrangement inside the chamber and activatingactuators in each housing at a different time.

[0070]FIG. 5 illustrates a preferred embodiment of the pump 10 formoving a fluid in a determined path. Actuators 12 are located in chamber14 in a pattern that defines the flow path for the liquid. Filledcircles indicate activated actuators and empty circles definenon-activated actuators. In FIG. 5 individual actuators are located atthe intersection of grid lines and a path for fluid 1 and fluid 2 areindicated. Fluid will flow along the paths defined by the empty circlesas contiguous activators in the pathway are activated. It is animportant aspect of the present invention that fluid may be caused toflow in a desired pattern by the present pump by activating certainactuators at a given time. Thus, as illustrated in FIG. 5 the two fluidsmay be caused to intersect by allowing actuators 14 a and 14 b to changedimensions of the non-activated state and by activating actuator 14 c.Fluid 2 will move in the new path and will combine with fluid 1.Reaction may occur at the intersection and the new fluid will bedirected out of the chamber by sequential activation of the actuators.

[0071]FIG. 6 is a view of the actuators in chamber 14 illustrating theindividual actuators 12 encased in an inert material 23. The actuatorsin FIG. 6 comprise photo-activated polymers. Conduits 24 for access to aphoto-source are illustrated. In certain embodiments of the pumpillustrated in FIG. 6, the actuators may be sequentially activated andfluid flows at a controlled rate. In other embodiments, the actuatorsmay be activated in a pattern that defines flow path of liquid. FIG. 6also illustrates ports 25 and 26 for receiving two fluids. The fluidsmay be directed in separate paths, as illustrated. Alternatively, thefluids may be directed to an intersection where they mix and react.

[0072]FIG. 7 depicts pump 10 in an on-line processing system whereinvarious fluids are directed into a main flowing fluid path at adetermined time. Inlet ports 15 a-e receive individual fluids. Eachfluid is directed in an individual flow path and is delivered to themain fluid at a determined time. Reactive products resulting fromreaction between the main fluid and individual fluids exit from exitport 16. This pump may be produced as a modular unit for insertion intoa chemical or bio-processing system. The modular unit comprises suitableconnectors 32 to achieve fluid connection with the on-line system.

[0073]FIG. 8 illustrates possible placements of contiguous actuators 12in chamber 14. FIG. 8A depicts the actuators on a chamber wall situatedin a position that allows each actuator to expand to an opposite hardsurface, be an opposite wall of the chamber or another surface in thechamber. FIG. 8B depicts the actuators situated apposite in the chamber.In this configuration, the actuators will expand into contact with theother. By placing the actuators opposite one another, actuators having asmaller strain will still effectively displace a large volume of fluid.In other configurations certain actuators may be in an interdigitatingpattern. This pattern may be used to provide a mixing of flowing fluid.

[0074]FIG. 9 illustrates pump 10 with electroactive actuators 12activated by contact with electrolytic solution. Actuator housing 11comprises chamber 14 and reservoir 27 for housing electrolyte solution28. Electrode 29 is located in the actuator and electrode 30 is locatedoutside the actuator Frit 31, a semi-permeable grid, separates actuatorand electrolyte solution. A semi-permeable membrane 32 surrounds theactuator.

[0075]FIG. 10 illustrates pump 10 as a propulsion device. FIG. 10aillustrates the pump for moving an object along a surface. FIG. 10billustrates the pump for moving an object suspended in a liquid. In FIG.10 the actuators deform or bend when activated so the force exerted bythe activated actuators has a directional component. In FIG. 10a thedirection of propulsion will be in a linear direction depending on thedirection of force. In FIG. 10b the direction of propulsion may be madeto circular or circuitous by positioning the actuators at locations thatunbalance total displacing force.

[0076] The pump and actuator housing of the present invention may bemade by methods well known in the art. The actuator housing may befabricated from materials such as polytetrafluoroethylenes, crystallinehomopolymer acetal resins, polysulfones, polyurethanes, polyimides,polycarbonates, polymethylmethacrylates and similar polymers, moldableor machinable glasses, ceramics, silicon wafers and any other materialthat is, or can be, rendered nonconductive, rigid, and chemically inert.In certain embodiments, a porous member or frit is located between theactuators and an electrolyte solution. The frit may be glass, a porouspolymer, such as for example polypropylene, or a porous non-corrodingmetal, such as, for example, nickel.

[0077] The actuator housing is preferably made by injection moldingusing a non conductive polymer. A chamber of the desired shape is formedinside the housing. First a flexible circuitry will be positioned in themold cavity, the mold will be closed and positioned and injected withthe molten polymer or similar material. The part will be removed fromthe mold and flashing removed. At this point, any secondary operationssuch as machining or drilling holes will be performed. Next, theactuators are installed in the chamber and a porous first is placedbetween the polymer and a reservoir containing electrolyte solution. Thenext step will be to make and attach electrical connections andcomponents not already molded into the housing. Following this, theelastomeric liner will be attached, if needed, and electrolyte added.

[0078] Preferred Embodiment

[0079] In the preferred embodiment the actuators comprise an EAPmaterial that swells from a PH change induced by irradiation of a lightspectrum to the material. The swelling would be caused by a diffusion ofelectrolyte ions through the multilayered gel although this is a slowprocess it is compensated for by the addition of more active fluidchannels in the housing. For example if one channel produced a flow rateof 1 ml per hr ten channels would produce 10 ml pr hr. A tuned photonicschip and optical fiber conduit would enable a single light source todeliver controlled irradiation to each actuator thereby reducing powerconsumption needs over the option of individual light sources for eachactuator.

[0080] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A pump for moving a fluid comprising: a. an actuator housing having achamber for housing the fluid, the chamber having ports foraccommodating fluid flow through the chamber; b. a plurality ofindividual actuators located in the chamber and in contact with thefluid; c. an activator for sequentially activating individual actuators,wherein each actuator, when activated, changes dimensions and exerts adisplacing force on the housed fluid.
 2. The pump of claim 1 wherein theactuator housing comprises two or more chambers for housing the fluid inflow connection.
 3. A pump for causing a fluid to flow at a determinedrate comprising the pump of claim 1 wherein the activator is designed toactivate individual actuators at a time and sequence selected todisplace the fluid at the chosen rate.
 4. A pump of claim 1 comprisingin addition a controller for the actuator whereby individual actuatorsare activated at a determined time.
 5. The pump of claim 4 wherein thecontroller is a programmable microprocessor in electrical connectionwith the activator.
 6. The pump of claim 4 comprising in addition asensor means for determining physical properties of the fluid whereinthe sensor is in electrical connection with the controller and iscapable of delivering signals received from the fluid to the controller.7. The pump of claim 1 wherein the physical properties to be sensed areselected from the group consisting of chemical composition, pH,pressure, temperature and flow rate.
 8. A pump for moving a fluid in adetermined path comprising the pump of claim 1 wherein the positions ofthe actuators in the actuator housing are selected to define the flowpath for the liquid when displaced.
 9. The pump of claim 8 wherein theactuator housing comprises more than one inlet port each port beingcapable of receiving an individual fluid and wherein individual flowpaths are determined for each fluid.
 10. The pump of claim 8 comprisingtwo or more outlet ports.
 11. The pump of claim 9 wherein the flow pathsof individual liquids are allowed to intersect and thereby allow mixingof the displaced fluids.
 12. A pump for moving a fluid at a determinedrate and in a determined path comprising the pump of claim 1 whereinsaid actuator sequentially activates individual contiguous actuators ata selected time and the actuators are located on one or more walls ofthe inner cavity at positions selected to define a flow path for thedisplaced liquid when the actuators are activated.
 13. The pump of claim1 wherein the actuator housing is located inside a chamber containingthe fluid, the chamber being a component of an on-line fluid processingsystem and the inlet port and outlet ports of the actuator housing areon the axis of flow in the fluid processing system.
 14. The pump ofclaim 1 comprising in addition a connector for coupling the actuatorhousing into an on-line processing system.
 15. The pump of claim 1wherein at least one of said actuators is positioned near the inlet portof the actuator housing and, when activated, forms a barrier preventingbackflow of fluid from the actuator housing.
 16. The pump of claim 1comprising in addition an elastomeric impermeable lining located betweenthe actuators and the housed fluid to prevent contact of the actuatorsand the fluid.
 17. The pump of claim 1 wherein the actuators areessentially inert and non-reactive with the fluid.
 18. The pump of claim16 wherein the actuators are biocompatible.
 19. The pump of claim 1wherein individual actuators are each encased in an essentially inertmaterial.
 20. The pump of Claim 19 wherein the material issemi-permeable to electrolytes.
 21. The pump of claim 17 wherein thematerial is non-permeable.
 22. The pump of claim 1 wherein the actuatorsare reversibly responsive elastomeric materials selected from the groupconsisting of electroactive polymers, electrolytically activated polymergels, optically activated polymers, piezoelectric polymers,piezoelectric ceramic materials, chemically activated polymers,magnetically activated polymers, magnetically activated polymers andshape memory polymers.
 23. The pump of claim 1 wherein the actuatorscomprise electroactive polymers.
 24. The pump of claim 23 wherein eachactuator is electrically shielded from contiguous actuators.
 25. Thepump of claim 23 comprising an electrical circuit for activatingindividual actuators at a determined time.
 26. The pump of claim 23comprising in addition a microprocessor in electrical contact with theelectrical circuit, the microprocessor being programmed to drive theelectrical circuit at a determined time whereby individual actuators areactivated at a determined time and sequence.
 27. The pump of claim 1wherein the actuators comprise electroactive gels that are activated bycontact with electrolyte.
 28. The pump of claim 27 comprising areservoir for housing an electrolytic solution.
 29. The pump of claim 28comprising a permeable frit between the actuator and the electrolyticsolution.
 30. The pump of claim 1 wherein the actuators are polymer gelsactivated by contact with an electrolytic solution, individual polymersare each encased with a semi-permeable material, the actuator housingcomprises a reservoir for housing electrolytic solution and a fritlocated between the reservoir and the actuator and the activator meansis an electrical circuit whereby electrolytic solution is caused to flowthrough the frit and semi-permeable material from the reservoir intocontact with the polymer and away from the polymer to cause reversibledimension change of the actuator.
 31. The pump of claim 30 wherein theelectrical circuit is operated by a remote control device.
 32. The pumpof claim 31 wherein the remote control device is infrared orradio-frequency driven.
 33. The pump of claim 31 wherein the remotecontrol device comprises a microprocessor programmed to activate theactuators at a selected time and sequence.
 34. The pump of claim 1wherein the actuators comprise optically responsive polymers.
 35. Thepump of claim 34 wherein the optically responsive polymers are ionizedin the presence of light.
 36. The pump of claim 34 wherein the opticallyresponsive polymers change pH in the presence of light.
 37. The pump ofclaim 36 wherein the polymers comprise anthracene.
 38. The pump of claim34 wherein the activation of the optically active polymers is controlledby exposure to a laser beam of specific wavelength, natural light, a LEDor a quantum light source.
 39. The pump of claim 38 wherein the time oflight exposure is controlled by a remote control device.
 40. The pump ofclaim 39 wherein the remote control device is infrared orradio-frequency driven.
 41. The pump of claim 34 wherein the controldevice is driven by a microprocessor programmed to activate theactuators at a selected time and sequence.
 42. The pump of claim 1wherein the actuators comprise electroactive polymers that a directlyactivated by signal from an electrical circuit.
 43. The pump of claim 1wherein the actuators comprise a chemically activated polymer.
 44. Thepump of claim 1 wherein the actuators comprise a magnetically activepolymer.
 45. The pump of claim 1 wherein the actuators comprise athermally active polymer.
 46. The pump of claim 1 wherein the actuatorscomprise shape memory alloys.
 47. The pump of claim 1 wherein theactuators comprise ceramic piezoelectric actuator.
 48. The pump of claim1 wherein the actuators comprise polymer/ceramic piezoelectriccombinations.
 49. The pump of claim 11 as a fluid mixing device.
 50. Apump for propelling an object along a surface comprising: a. an actuatorhousing in contact with the object; b. a plurality of contiguousactuators in contact with the actuator housing and in contact with thesurface; and c. an activator for sequentially activating individualactuators, wherein each actuator, when activated, changes dimensions andexerts a displacing force on the surface and thereby propels the solidobject in a direction opposite that of the displacing force.
 51. Thepump of claim 50 for propelling an object suspended on a liquid surface.52. The pump of claim 50 for propelling an object suspended on a solidsurface.
 53. The pump of claim 50 for propelling an object submerged ina liquid.
 54. A method of pumping a fluid at a controlled ratecomprising placing the actuator housing of claim 1 into fluid contactwith the fluid, activating a first actuator to prevent back-flow fromthe actuator housing and then repeatedly activating the contiguousactuators at a sequence wherein activation of one of the individualactuators occurs at a time after one of its contiguous actuators hasbeen activated.
 55. The method of claim 54 for pumping fluids ofdifferent viscosities wherein the pump comprises two or more actuatorhousings in fluid connection and each actuator housing is operated at adifferent flow rate.
 56. The pump of claim 1 as an implantable infusionpump.
 57. The pump of claim 1 as a drug delivery device for delivering aliquid drug or drug solution at a controlled rate and at a controlledtime to an individual wherein the actuator housing comprises a singleoutlet port but no inlet port and houses the liquid drug or drugsolution to be delivered.